665784775 has 6 divisors (see below), whose sum is σ = 825573152. Its totient is φ = 532627800.

The previous prime is 665784761. The next prime is 665784827. The reversal of 665784775 is 577487566.

It is not a de Polignac number, because 665784775 - 2¹⁵ = 665752007 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 13315671 + ... + 13315720.

Almost surely, 2^665784775 is an apocalyptic number.

665784775 is a deficient number, since it is larger than the sum of its proper divisors (159788377).

665784775 is a wasteful number, since it uses less digits than its factorization.

665784775 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26631401 (or 26631396 counting only the distinct ones).

The product of its digits is 9878400, while the sum is 55.

The square root of 665784775 is about 25802.8055645118. The cubic root of 665784775 is about 873.1950930923.

The spelling of 665784775 in words is "six hundred sixty-five million, seven hundred eighty-four thousand, seven hundred seventy-five".